posix_cpu_timer: Exit early when process has been reaped

commit 2c13ce8f6b2f6fd9ba2f9261b1939fc0f62d1307 upstream.

Variable "now" seems to be genuinely used unintialized
if branch

	if (CPUCLOCK_PERTHREAD(timer->it_clock)) {

is not taken and branch

	if (unlikely(sighand == NULL)) {

is taken. In this case the process has been reaped and the timer is marked as
disarmed anyway. So none of the postprocessing of the sample is
required. Return right away.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Link: http://lkml.kernel.org/r/20160707223911.GA26483@p183.telecom.by
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index f5e86d2..80016b3 100644 (file)
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -808,6 +808,7 @@ static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
                        timer->it.cpu.expires = 0;
                        sample_to_timespec(timer->it_clock, timer->it.cpu.expires,
                                           &itp->it_value);
+                       return;
                } else {
                        cpu_timer_sample_group(timer->it_clock, p, &now);
                        unlock_task_sighand(p, &flags);